UE5-MCP-Server

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ue5_set_property

Sets a UProperty value on any UObject in Unreal Engine 5 with undo support. Use setter functions for component properties that are unavailable remotely.

Instructions

Sets the value of a UPROPERTY on a UObject. Supports undo (Ctrl+Z). NOTE: Component properties (e.g., RootComponent, LightComponent) are often unavailable remotely. Use ue5_call_function with setter functions like SetActorScale3D instead.

Tool call template

Replace each placeholder with a value matching the input schema. Only required parameters are included; add optional parameters as needed.

{
  "id": 1,
  "jsonrpc": "2.0",
  "method": "tools/call",
  "params": {
    "arguments": {
      "objectPath": "<objectPath>",
      "propertyName": "<propertyName>",
      "value": "<value>"
    },
    "name": "ue5_set_property"
  }
}

Input Schema

Name	Required	Description
`objectPath`	Yes	The path to the UObject.
`propertyName`	Yes	The name of the property to set.
`value`	Yes	The value to set the property to (can be string, number, boolean, object, or array).

Schema Changelog

Changes observed during successful MCP inspections.

First observedv1.0.0Jun 18, 2026

TDQS

A4.4/5.0

Behavior4/5

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

No annotations provided, so description carries full burden. It discloses undo support and the remote unavailability of component properties, but lacks detail on side effects or permissions.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Conciseness5/5

Is the description appropriately sized, front-loaded, and free of redundancy?

Two sentences plus a note, front-loaded with the primary action, every sentence adds necessary information without fluff.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Completeness4/5

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

Adequate for a simple setter with full schema coverage; covers undo, caveats, and alternatives but could mention return behavior (e.g., success/failure) since no output schema exists.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Parameters3/5

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, baseline 3. The description adds no additional meaning beyond the schema; the note about component properties relates to usage rather than parameter semantics.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Purpose5/5

Does the description clearly state what the tool does and how it differs from similar tools?

The description specifies the exact verb 'sets' and resource 'UObject property', clearly distinguishing from siblings like ue5_call_function and ue5_set_material.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Usage Guidelines5/5

Does the description explain when to use this tool, when not to, or what alternatives exist?

Explicitly states support for undo and warns against component properties, providing a concrete alternative (ue5_call_function with setter functions) for those cases.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.